About Boron Family
The name Boron has come from the Arabic word, ‘buraq’ which is referred to as the borax name. Boron belongs to the 13th group in the p-block element. The 13th group elements can be given as aluminium, boron, gallium, thallium, and indium. All these are metallic in nature except boron, whereas it is a metalloid. Also, all of them have 3 electrons in the outermost shell with the electronic configuration of ns2np1. There are two oxidation states (+1 and +3) of the boron family.
Boron Family Explained
Boron is a non-metal, whereas aluminium, which is the second element, is a metal. Indium, gallium, and titanium are almost metallic in nature. Also, aluminium is one of the essential members of the boron family, having an atomic number of 13 with the chemical symbol is ‘Al.’ It is very expensive to form aluminium because, for the electrolysis of one mole of aluminium, we need three moles of electron and therefore a huge amount of energy is used.
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Occurrence of Boron Family
Boron can be found in limited quantities. Mostly, it is a product of the barrage of subatomic particles that are created from the radioactivity characteristic. On our planet, aluminium is readily available. Also, it is the third most copious element present outside of the Earth (8.3%).
Gallium can be found on the earth including a wealth of 13 parts per one molecule. Indium has also been considered as the 61st richest element in the covering of the world. At the same time, Thallium is scattered in smaller amounts all over the planet. Ununtrium is not available naturally, and therefore, it has been named as a synthetic element.
Physical Properties of Group 13 Elements
Let us look at the physical properties of the Boron family, as listed below:
Indium has a lesser nuclear radius compared to Thallium. This is due to the lanthanide compression.
As we move down the group, the +1 oxidation state turns out to be steadier than that of +3 states. This is primarily due to the inert pair impact.
Boron holds a high melting point, and this is due to the icosahedral structure. Gallium has the lowest melting point in the boron family.
All the elements of the boron family blaze in oxygen at high temperatures raising M2O3.
Aluminium is an amphoteric compound. It means the metal disintegrates in weakened mineral acids and in the sodium hydroxide (aqueous).
If we move down the group, the acidic nature of hydroxides reduces.
Boric acid is also an extremely delicate monobasic acid.
Chemical Properties of Group 13 Elements
The dissociation of group 13 elements needs a lot of energy. This is due to the compounds formed by the Group 13 elements with oxygen are thermodynamically inert.
Also, boron chemically acts as a non-metal. However, the remaining elements exhibit metallic properties. Why does this happen? Because a large portion of the irregularities, which is seen in the properties of the group 13 elements will be attributed to the expansion in Zeff (an Effective Nuclear Charge). This emerges from the atomic charge's weakened protection by the filled subshells of (n − 1) d10 and the (n − 2) f14.
Instead of shaping the metallic grid with the delocalized valence electrons, Boron frames the special aggregates, containing multicenter bonds. This includes the metal borides, where boron attaches to the other boron iotas. This arrangement forms the three-dimensional bunches or systems with consistent geometric structures.
All the neutral compounds of group 13 elements can be said as the electron lacking elements and act as Lewis acids. Whereas, the trivalent halides of the heavier elements shape halogen-connected dimers, consist of the electron-match bonds, as opposed to the delocalized electron-lacking bonds, which are typical for the diborane.
Their oxides can break down in weakened acids, in spite of the fact that gallium and aluminium oxides are amphoteric. The elements of group 13 never react with the hydrogen atom due to the valency of hydrogen is one, to that of the boron family, as three. The trihalides of group 13 elements are the strong Lewis acids because they have the tendency to produce the compounds with the electron-pair donors, which are the Lewis bases.
Applications of the Boron Family
We can use Boron commonly in fiberglass, and it also finds usage in the ceramics market. We can use it in the making of pots, vases, plates, and more because of its greater insulating properties.
Aluminium is utilized frequently as a part of electrical gadgets, construction materials, and particularly as a transmitter in links. We can also use it in vessels and apparatuses for cooking and safeguarding the food materials. The absence of aluminium reactivity with food items makes it helpful for canning, especially.
The aluminium compound is a part of alloys that we use primarily for making the lightweight bodies used for flying machines.
Gallium arsenide is a common part of enhancers, semiconductors, solar cells, and more.
We can also use Gallium amalgams for huge dental purposes. Gallium ammonium chloride finds common use in the leads in transistors. A notable use of gallium is in LED lighting.
FAQs on Boron Family in the Periodic Table
1. What are the elements that constitute the Boron Family (Group 13) in the Periodic Table?
The Boron Family, or Group 13, is the first group within the p-block of the periodic table. It includes the following six elements:
- Boron (B) - A metalloid
- Aluminium (Al) - A metal
- Gallium (Ga) - A metal
- Indium (In) - A metal
- Thallium (Tl) - A metal
- Nihonium (Nh) - A synthetic, radioactive element
A key characteristic of this family is that each element has three valence electrons in its outermost shell.
2. What is the general electronic configuration of the Boron Family elements?
The general electronic configuration for the elements of the Boron Family is ns²np¹. This indicates that they have two electrons in the s-orbital and one electron in the p-orbital of their valence shell. For example, the configuration for Boron is [He] 2s²2p¹, and for Aluminium, it is [Ne] 3s²3p¹.
3. What are the general trends in physical properties observed in the Boron Family?
The physical properties of Group 13 elements show distinct trends as you move down the group:
- Atomic Radius: Generally increases down the group, but with an important exception where Gallium (135 pm) is slightly smaller than Aluminium (143 pm).
- Ionisation Enthalpy: Decreases down the group, but not smoothly. The value for Thallium is higher than that of Indium due to the poor shielding of inner d- and f-electrons.
- Metallic Character: Increases down the group. Boron is a metalloid, while Aluminium, Gallium, Indium, and Thallium are distinctly metallic.
- Electronegativity: First decreases from Boron to Aluminium and then increases slightly down the rest of the group.
4. Why does gallium have a smaller atomic radius than aluminium, breaking the general trend?
This anomaly is due to the poor shielding effect of the d-electrons. Gallium is the first element in the group to have a filled d-orbital (10 d-electrons). These d-electrons are not effective at shielding the outer valence electrons from the pull of the nucleus. As a result, the effective nuclear charge on Gallium's outer electrons is higher than expected, causing its atomic radius to be smaller than Aluminium's.
5. How does the chemical reactivity of Group 13 elements change down the group?
The chemical reactivity of Boron Family elements shows a clear progression. Boron is relatively unreactive at normal temperatures except with strong oxidising agents. Aluminium is highly reactive but is often protected by a passive oxide layer. As we move down the group from Gallium to Thallium, reactivity increases. They react with air to form oxides and with halogens to form trihalides (MX₃). The nature of their compounds also shifts from being predominantly covalent (for Boron) to ionic (for heavier elements).
6. Why does aluminium not react with pure water despite being a reactive metal?
Aluminium does not react with pure, cold water because a very thin, tough, and non-porous protective layer of aluminium oxide (Al₂O₃) instantly forms on its surface upon exposure to air. This chemically inert layer acts as a barrier, preventing the underlying metal from coming into contact with water and thus inhibiting any reaction.
7. What is the 'inert pair effect' and how does it influence the chemistry of the Boron Family?
The inert pair effect is the tendency of the two electrons in the outermost s-orbital (the ns² electrons) to remain unshared or 'inert' in compounds of heavier p-block elements. In the Boron Family, this effect is most significant for Thallium (Tl). Because of this effect, Thallium's +1 oxidation state is more stable and common than its +3 oxidation state, unlike the lighter elements which predominantly show a +3 oxidation state.
8. Why is boron considered a metalloid while other Group 13 elements are metals?
Boron exhibits anomalous behaviour due to its unique properties. It has a very small atomic size, extremely high ionisation enthalpy, and high electronegativity compared to other elements in the group. The large amount of energy required to remove its three valence electrons prevents it from forming a B³⁺ ion. Instead, it prefers to form strong, stable covalent bonds, which is a characteristic of non-metals. This combination of properties gives Boron its metalloid character.
9. Why do boron compounds like Boron Trifluoride (BF₃) act as excellent Lewis acids?
A Lewis acid is a substance that can accept a pair of electrons. In Boron Trifluoride (BF₃), the central boron atom forms three single covalent bonds with three fluorine atoms. This leaves the boron atom with only six electrons in its valence shell, resulting in an incomplete octet. To achieve a stable electronic configuration, the electron-deficient boron atom has a strong tendency to accept a lone pair of electrons from a donor molecule (a Lewis base), making BF₃ a powerful Lewis acid.
10. What is the origin of the name 'Icosagens' for the Boron family?
The alternative name 'Icosagens' for the Boron family comes from the Greek word 'eikosi', which means 'twenty'. This name is a reference to the icosahedron, a geometric shape with 20 faces. This structure is a fundamental building block in the crystalline forms of elemental boron and many of its complex compounds, such as boranes and borides.
